Hi. Had a friend get me into saltwater aquarium...then he stopped talking to me(lol), so I need some advice on some things. I have a 40 gal long,crushed coral bottom, yellow tang, pygmy angel, 2 turbo snails, 1 zebra snail, 1 arrow crab, 1 damsel(small). I have an Emperor 400 bio-wheel(80 gal) filter, and a Cascade 35 gal filter. On Thursday, 6/15, I noticed a slight cloudiness to my water...Friday I couldn't see my backdrop. I changed the cascade filter, and one of the Emperor filters, and a 15 gal. water change. No help. Can I get some advice please?

What kind of lights/how long are you running them?
Do you have a test kit, if so, what are your results?
How long has the tank been running?
You can put your yank specs/equipment/critters under "my info" so we will know what you have and any new critters that you might add.

__________________Age is relative, you are only as old as you act....of course, this works in reverse....

check your salinity/specfic gravity. maybe there's too much salt in there from the water change.

Or, maybe your crushed coral was not rinsed well enough when you filled it, and it has a lot of dust underneath (crushed coral is INCREDIBLY dusty.) Your substrate could be getting stirred up by the janitors, releasing all that dust into your water...

I would get the water back to acceptable levels immediately! I would do a 50% water change to start with and add a protein skimmer. I couldn't believe the nasty slimy gunk the protein skimmer took out of my water. It's been a while since I kept salts and its hard to tell whats going on with your tank with the little info provided. I'm also far from a salt expert but the thought of you losing these guys just makes my stomach hurt! Good luck and keep us posted on the outcome.